Vehicles equipped with internal combustion engines are fitted with catalytic converter systems which convert certain products of combustion of the engine such as HC, CO, NO.sub.x, into emissions which are not considered noxious such as CO.sub.2, H.sub.2 O, and N.sub.2. Legislation (federal, state and foreign) increasingly limits the amount of noxious emissions which can be emitted to the atmosphere. Typically, the legislation imposes a specified limit of noxious emissions which can be discharged to the atmosphere during the time any given vehicle is operated at a specified or regulated drive cycle such as an FTP (Federal Test Protocol), US06 (High speed, heigh acceleration portion of the Supplemental Federal Test Procedure), SC03 (Air conditioner operation mode of the Supplemental Federal Test Procedure), European MVEG-A drive cycle etc. The drive cycles include or will include a "cold-start" segment which typically contributes a significant portion of the total noxious emissions discharged to atmosphere during the entire drive cycle. How the engine is operated determines to a large extent the make-up of the products of combustion and specifically, the generation of the regulated emissions by the engine which must be converted by the catalytic converter.
The engine and other vehicular functions are under the control of an electronic controller referred to as an engine control module (ECM) or an engine control unit (ECU) which is now a very sophisticated, dedicated microprocessor(s). The ECU receives a number of input signals from a variety of sensors and causes the generation of a number of output signals sent to various actuators on the engine and vehicle for controlling engine and vehicle functions. Insofar as the invention is concerned, the ECU will generate a signal to the engine's fuel injectors controlling the pulse width of the injector, i.e., the pressure, timing, rate and duration of injection, which is matched with the air (flow and pressure) that is mixed with the fuel to produce a combustible mixture, i.e., see U.S. Pat. No. 5,261,366 to Regueiro issued Nov. 16, 1993 for a discussion of various injector pulse techniques. In addition, the vehicle is typically equipped with a TWC catalyst (3-way catalyst converting NO.sub.x, CO, and HC) and the air to fuel ratio (A/F) will cycle under ECU command at fixed perturbations from one A/F condition to another A/F condition. Typically, the A/F ratio will cycle about stoichiometric from a rich to a lean condition (although lean burn technology will cycle the A/F ratio from a lean to a less lean condition). In some newer, state-of-the-art vehicles, the A/F ratio might be held constant at stoichiometric condition or other suitable A/F ratio value, without any perturbations. In addition, the ECU will control spark timing through a spark module (and the valve timing, if the vehicle is equipped with variable valve timing). The ECU is programmed, closed loop (although open loop with respect to emission sensor feedback during cold-start), to generate actuator signals to the injector and to the engine timing module to produce an engine operation which assures vehicle driveability while producing products of combustion having compositions such that noxious emissions in the products of combustion can be converted by the catalytic converter to meet emission regulations and/or engineering targets.
The ECU is calibrated by the manufacturer generating look-up tables or maps while performing specified drive cycles during which emission data is obtained, i.e., See 40 CFR chapter 1, sections 86 et al. Reference can be had to U.S. Pat. No. 5,835,974 to Nagy for a description of a method to calibrate a bench gas analyzer suitable for collecting emission data in conformance with CFR emission analysis procedures. The look-up tables establish spark advance, valve timing, air/fuel ratio and EGR (Exhaust Gas Recirculation) settings for various engine speed/torque conditions occurring during the drive cycle. See for example, the calibration procedures set forth in U.S. Pat. No. 4,438,497 to Willis et al. The maps or look-up tables generate a code programmed by the ECU which is specific and unique to each engine for a given vehicle platform. Each manufacturer has its own proprietary ECU and within each manufacturer there are literally hundreds of unique and specific ECU calibrations. See U.S. Pat. No. 5,473,540 to Schmitz issued Dec. 5, 1995 proposing a generic ECU having ability to be programmed for any specific vehicle through a separate memory module. In addition, the automotive manufacturers are moving away from part suppliers in favor of suppliers who can furnish complete systems for drop-in assembly in the vehicle. In-so-far as the present invention is concerned, a supplier will furnish the entire catalytic converter system suitable for a specific vehicular platform produced by the automobile manufacturer as opposed to a supplier furnishing a catalytic converter for use in a catalytic converter system which the automobile manufacturer designs and mates with a specific engine in a specific vehicle. However, the ECU code and ECU details are proprietary and generally, not available to third party suppliers.
Within the prior art it is known to send false input signals to the ECU to simulate an aged condition such as an aged EGO sensor as shown in U.S. Pat. No. 5,522,250 to Gee et al. so that the ECU can be calibrated. On somewhat similar lines, U.S. Pat. No. 4,300,205 to Tansuwan shows a simulated controller capable of feeding false input signals to the ECU and also generating false output signals to certain output devices thus bypassing the ECU. In the '205 patent, the object is to test, calibrate and improve the speed control for any engine. In the interactive diagnostic area, U.S. Pat. No. 5,214,582 to Gray shows a modified break out box with bypass connections taking over control of selected sensors and actuators so that testing diagnosis of the sensors and actuators can be performed. In the '582 patent, simulated sensor and actuator signals are inputted from an external computer.
U.S. Pat. No. 5,396,794 to Nichols is somewhat similar to the '582 patent in that a break out box is used to bypass certain inputs and outputs of the ECU while allowing the ECU to function normally for processing signals which are not bypassed. The '794 patent periodically establishes ECU control to avoid a shut down mode and uses a CPU to control the bypass functions. In the '794 patent, the bypass system is disclosed for purposes of aging the catalytic converter by changing the injector's pulse width to produce excessive emissions which prematurely age the catalyst. The '794 patent is improved in U.S. Pat. No. 5,535,620 to Nichols in that ignition timing as well as the injectors can be separately and independently controlled irrespective of the ECU and without knowledge of the ECU's operating code. The object of the '620 patent is the provision of a programmable engine tool for conducting combustion research or emission control research (i.e., as explained in the '794 patent for catalytic converter aging), and as a diagnostic for the testing of the sensors and actuators. The Nichols patents, perhaps in a somewhat simpler form, and to some extent the Gray patent, are utilized in the present invention and are thus incorporated by reference herein
Until the present invention, a system did not exist which allowed a third party supplier without detailed knowledge of the operating code and details of the ECU to dynamically control the engine throughout its operating range such that a catalytic converter system could be specifically designed and mated with any engine to positively assure compliance with emission regulations and/or engineering targets.